Master control device for rolling mills and the like



Nov. 15, 1960 c. R. MITCHELL MASTER CONTROL DEVICE FOR ROLLING MILLS ANDTHE LIKE e 3 m \N 5 Nu a NW m s W 2 N \N \N \N U M Filed Oct. 3, 1956Avrewrnet (Uravmfflrma;

2 Sheets-Sheet 2 C. R. MITCHELL Nov. 15, 1960 MASTER CONTROL DEVICE FORROLLING MILLS AND THE LIKE Filed Oct. 3, 1956 Unite MASTER CGNTRULDEVICE FOR ROLLING mLS AND THE LIKE Filed Oct. 3, 1956, Ser. No. 613,787

1 Claim. (Cl. 8056) This invention relates generally to control devicesand more particularly to master control devices employed for adjustingrolling mill equipment and the like and enables an operator selectivelyto individually or simultaneously adjust the positions of the mill rollsat a plurality of mill stands.

In the rolling mill art, it is well known to employ screw down motors atthe various rolling stands to adjust the spacing between the respectivework rolls and thereby to adjust the thickness of the material beingrolled. However, it has not been proposed heretofore to provide a singlemaster control device, conveniently situated, and simple to operate forcontrolling the screw down motors at a plurality of standssimultaneously and yet which permits the stands to be separatelyadjusted when necessary.

It is therefore an object of this invention to provide an inexpensiveyet versatile master control device, conveniently situated, forsimultaneously adjusting a plurality of rolling stands in a rollingmill.

Another object of the present invention is to provide a master controldevice which simultaneously adjusts the work roll spacing at a pluralityof rolling mill stands while maintaining the load distribution betweenstands.

Another object is to provide a master control device which is adaptablefor use with other known control devices such as individual mill standcontrol devices and which makes the operation of the known devices moreversatile.

Another object of the present invention is to provide a control devicefor rolling mills and the like which speeds up the adjustment procedure,reduces waste, and cuts down on the number of operators.

Yet another object of the invention is to provide a control device foradjusting a plurality of mill stands in a rolling mill which reducestime normally lost changing the rolling operation.

Briefly, the present master control device is adapted to be employedwith rolling mills having a plurality of stands each of which isprovided with work rolls for reducing the thickness of sheet materialand each of which is provided with screw-down means for adjusting thepositions of the work rolls and comprises means connected to thescrew-down adjusting means at a plurality of rolling mill stands forsimultaneous adjustment thereof and means for locking out the individualstand adjusting means during said simultaneous adjustment.

Other objects and advantages of the present invention will becomeapparent after considering the following detailed description inconjunction with the accompanying drawings.

In the drawings:

Fig. l is a side elevational view, partly cut away, of a plurality ofspaced mill roll stands in a rolling mill,

Fig. 2 is a top plan view of the mill roll stands shown in Fig. 1,

Fig. 3 is a schematic wiring diagram showing illusice tratively one formof controls for the rolling mill stands shown in Figs. 1 and 2, and

Fig. 4 is a schematic wiring diagram showing the master control portionof the controls for the rolling mill.

Rolling mills that produce sheet material from bulkier forms, such asmills for rolling steel ingots into sheet steel, are in common use inmany phases of industry. Certain of these, because of the nature of thematerial being rolled, provide a plurality of rolling standsor stations,each performing part of the overall reduction in thickness. In suchmilling operations it is desirable, if not essential, to distribute thework load betweenthe various stands so that no single stand exceeds itsworking capacity and wears out prematurely. Furthermore, it is desirableto be able to adjust all of the stands simultaneously, or individually,if necessary, to quickly correct errors in the thickness of the finishedmaterial. Naturally, the production of oif-gauge material results inwaste, inefficiency and lost time, all of which are reduced by thepresent device. Still further, it is desirable to be able to make thesecorrective adjustments while maintaining a suitable distribution of workload between the stands. The drawings show a master control device,referred to by number 10 (Fig. 4), which is constructed according to theteachings of the present invention. The device 10 may be installed asoriginal equipment in a rolling mill or as an improvement on anestablished mill. In either case, the principles of operation and theadvantages thereof are substantially the same; namely, quicker moreversatile adjustment of the rolling stands, maintenance of loaddistribution between stands, less waste due to oil-gauge material, andefiicient operation with fewer operators.

Fig. lshows a plurality of spaced mill roll stands 12 in a sheet rollingmill such as for steel sheet W. Each mill stand 12 includes an upperwork roll 14, a lower work roll 16, an upper adjustable back-up roll 18and a lower stationary back-up roll 20. The work rolls 14 and 16 aredriven and frictionally engage and drive the back-up rolls 18 and 20respectively, and the stands 12 are adjusted by varying the spacingbetween the work rolls 14 and 16. Front and rear screw-down motors 22and 24 respectively, are provided on each of the stands 12 (Fig. 2). Theoperation of the screw-down motors 22 and 24 changes the work rollspacing and is under the control of switches and relays which will bedescribed hereinafter.

The screw-down motors 22 and 24 have shafts 26 and 28 respectively,which drive worm gears 30 and 31 operatively connected thereto. The wormgears 30 and 31 are meshed with gears 32 and 33 respectively and movefront and rear vertical screw-down members 34 and 36 that operate toadjust the positions of front and rear end bearing members. One bearingmember 38 is seen in Fig. l and the others are similar and have not beenshown. Shaft 42 in each stand carries the upper back-up roll 18, and byadjusting the vertical position of the shaft 42 and the associated roll18, the spacing between work rolls 14- and 16 is adjusted. The presentdevice could also be employed with various other stand constructions.For example, the back-up rolls 18 and 20 could be eliminated and thework rolls 14 and 16 adjusted directly, or the lower rolls 16 and 20could be adjusted instead of the upper rolls 14 and 18. In theembodiment shown for illustrative purposes, the Work rolls 14 are biasedupwardly against the rolls 18 in a manner well known in the rolling millart so that the material being rolled does not have to support the workrolls 14 and the back-up rolls 18 and so that the spacing between workrolls 14 and 16 is maintained.

By equipping rolling mills with the present device, complete flexibilityof stand adjustment is obtained. For

taneously to change the work roll spacing, they can be adjustedseparately (called jogging) to provide equal or unequal longitudinalspacing between the work rolls, they canbe adjusted in oppositedirections simultaneously when the error in longitudinal roll spacing isgreat, and they can be moved at high speed or at low speed as thesituation requires.

, The above adjustments as applied to an individual stand have beenknown in the milling art heretofore. However, where a plurality ofstands 12 are employed for a single rolling operation, the limitedindividual stand controls make it necessary to have an operatorpositioned at each stand 12 or else to move several operators from standto, stand to make adjustments. The disadvantages of such operation areobvious; it means that for each adjustment the distribution of workbetween the stands is altered, it means valuable time is wasted makingadjustments, it means off-gauge material is rolled while adjustments arebeing made, it means constantly rechecking'the thickness of the finishedmaterial, and it means a large number of operators are required to makeadjustments.

To overcome these disadvantages, the present device, which is embodiedin a master control switch 46 and related electric circuits, isincorporated into a mill control system.

The master control switch 46 is provided with five operating positions(Figs. 3 and 4). In the central or de-energized position 48, the switch46 is inoperative and each of the mill stands 12 can be adjusted (orjogged) individually as described above. In the other four positions 50,52, 54 and 56, the individual controls for the stands 12 are locked outand rendered ir1- operative, and the master control switch 46 hascomplete control over the adjustment of the stands 12. Furthermore, inthe positions 50, 52, 54 and 56 the adjustment of all the aifectedstands is simultaneous and is in the same direction.

In positions 50 and 54, which are the control points for adjusting allmills upwardly, the master switch 46 operates to move all of thescrew-down members 34 and 36 upwardly in a direction to increase thespacing between work rolls 14 and 16. In positions 52 and 56, the millsare downwardly adjustable. Positions 54 and 56, are employed with thepositions 50 and 52 respectively, to increase the speed of adjustment byoperating the screw-down motors 22 and 24 at higher speed. Conventionalmotor control circuits are employed for this purpose, and indicated at47 (Fig. 3).

The switch 46 is located near the final stand 12. This permits anoperator positioned there to observe the thickness (on any suitablegauge) of the finished material coming out of the final mill roll stand12 and to make necessary corrective adjustments. Whenever an error inthickness is detected by the operator, he can make the necessarycorrection by operating the master switch 46 without changing hisposition and without changing the relative work loads of the stands 12.Furthermore, should an individual stand need jogging or individualadjustment, this can be accomplished (while the mill is operating) withthe master switch 46 in the de-energized position 48.

Schematic wiring diagrams, including the circuit elements employed withthe switch 46, are shown in Figs. 3 and 4. The circuit diagrams havebeen greatly simplified to make them easier to understand.

Fig. 4 illustrates diagrammatically the electrical components associatedmost directly with the switch 46. Also diagrammatically shown are thefive operating positions (48, 50, 52, 54 and 56) of the switch 46. Whenthe switch 4 6 is in the inoperative or neutral position 48 (which isthe locked out position), relay 60 is energized. The relay 60 whenenergized causes transfer contact points 62 (Fig. 3) to establishcircuits that enable the various stands 12 to be separately controlledfor jogging and the like. The contacts 62 are shown in Fig. 3 gangedtogether so that they all engage their associated left-hand contactterminals 64:: and 64b in the de-energized position of relay 6%. Whenthe relay 6% is energized (as it is in position 48 of the switch 46),the transfer contacts 62 engages stationary terminals 66a and 6612instead and the individual stand controls are then operative. When relay6i) is de-energized, spring 68 (Fig. 3) causes the contacts 62 to moveto their left positions. In Fig. 3, the transfer contacts 62 are shownfor the sake of clarity at an intermediate position midway betweenstationary contacts 64 (a and b) and stationary contacts 66 (a and b).

In the locked out position (with relay 6% energized and the contacts 62in their rightward positions), circuits are available from everyscrewdown motor to the individual stand up and down switches 76, 72, and74. The push button switches 76' (which are connected to a source ofenergy indicated by the symbols 8+) when operated move the singleassociated screw-down motors up. Similarly, switches 72 are operated toindividually move the associated screw-down motors 22 or 24 down. Switch'74 at each station 12 is provided with a transfer contact 76 and twocooperating normally open contacts 78 and 80. The contact 78 isconnected to both of the up switches at the associated stand 12- and tothe up terminals on the associated front and rear screw-down motors 22and 2 4. The contact 36 is similarly connected to both of the downswitches '72 and to the down terminals on the associated front and rearscrew-down motors 22 and 24. When the transfer terminal 76 at a stand ismoved into engagement with the terminal 78 (and switch 46 is in position48), both the front and rear screw-down motors 22 and 24 at theassociated stand 12 move up wardly together, and when the transferterminal 76 is moved downwardly into engagement with the contact 80, theassociated front and rear screw-down motors 22 and 24 move downwardlytogether.

The individual stand controls (under control of switches 76, '72, and74) are dependent upon the lock out relay 60 being energized. This inturn depends upon the master control switch 46 being in the centralposition 48. If the master switch 46 (Fig. 3) is moved into any otherposition, the relay 6% becomes de-energized and all of the transfercontacts 62 move to the left into engagement with the contacts 64a and64b.

In positions 59 and 54 of the switch 46, a circuit is available from 13+through the switch operating arm 82 (which is a conductor) to thecontact at positions 51 and 54, and from there upwardly on line 81 toall of the terminals 64:: corresponding to the up connections on thescrew-down motors 22 and 24.

if the switch 46 is moved to either of the right positions 52 and 516,the relay (ii) is again de-energized and a circuit is available frompositions 52 and 56 on line 83 to all the down terminals 64b. Therefore,in positions 50 and 54 all of the screw-down motors 22 and 24 aresimultaneously energized to increase the spacing between the work rolls1d and 16, and in positions 52 and 56 all of the screw-down motors 22and 24- are simultaneously energized to decrease the spacing between thework rolls.

When the switch 46 is moved into positions 54 and 56, an additionalterminal is contacted by the switch operating arm 82 which energizesadditional circuitry to means 4 for increasing the speed of thescrew-down motors 22 and 24. Therefore, in positions 54 and 56, circuitsare available to energize all of the screw-down motors 22 and 24 at highspeed in their respective directions. The increased speed at which thescrew-down motors operate when the master switch 46 is in positions 54,and 56, speeds up the adjusting procedure and is particularly handy whenchanging over from one rolling operation to another.

In Fig. 4-, the five positions of the switch 46 are showndiagrammatically to further illustrate the operation. In

the various positions of the switch (48, 5%, 52, 54 and 56) the switch46 energizes a different control relay. In position 48, as describedabove, the relay 60 is energized, in position 50, relay 84 (theall-mills-up relay) is energized, in position 52, the relay 86 (theall-mills-down relay) is energized, and in positions 54 and 56, relay 88(the all-mills-high speed relay) is energized. Relay 90 is alsoconnected across the lines to the switch 46. The relay 90 has normallyopen contacts connected in series with relays 84, 86 and 88 for voltageprotection thereof.

It is now apparent that a control device has been provided for rollingmills that employ a plurality of reducing stands that simultaneouslyadjusts a plurality of the stands. Furthermore, a master control devicehas been provided which enables the stands to be individually adjustedto compensate for wear and/or unequal distribution of load.

Thus, it is apparent that there has been provided a novel master controldevice for rolling mills that fulfills all of the objects and advantagessought therefor. It is to be understood that the foregoing descriptionand accompanying drawings have been presented only by way ofillustration and example and that changes and alterations in the presentdisclosure which will be apparent to those skilled in the art arecontemplated as being Within the scope of this invention which islimited only by the claim which follows.

What I claim is:

Means for controlling the thickness of sheet material being reduced by arolling mill operation comprising a rolling mill having a plurality ofspaced unidirectional roll stands, each of said stands having spacedupper and lower work rolls and means thereat for changing the positionof one of said work rolls relative to the other work roll to adjust thespacing therebetween, said last named means including for each of saidstands separate motor means operatively connected to each end of saidone work roll, and control means including electric circuit means,switch means, and speed and direction control means connected to each ofsaid separate motor means, said switch means being selectively movableto a plurality of difierent operating positions to individually orsimultaneously energize the motor means at the associated stand in 'adesired direct-ion and at a desired speed to elfect adjustment of thespacing of the Work rolls thereat, said motor means being capable ofbeing energized during a material reducing operation; and master controlmeans operatively connected to the motor means and the individual standcontrol means at a plurality of said stands and including multi-positionmaster switch means, electric circuit means and motor speed anddirection control means, said master switch means being movable to aplurality of different operating positions to efiect simultaneousenergization in a selected direction and at selected speed of the motormeans at said plurality of stands, said master control means beingeffective during material reducing operations and including means fordisabling the control means at the individual stands during operationthereof.

References Cited in the file of this patent UNITED STATES PATENTS1,466,642 Crook Aug. 28, 1923 1,764,312 Ienks June 17, 1930 2,017,040Dahl Oct. 15, 1935 2,106,965 Wright Feb. 1, 1938 2,124,518 Marquart July19, 1938 2,564,284 Schurr Aug. 14, 1951 2,708,254 Macaulay et al. May10, 1955

